A mouse is a well known and relatively simple user interface tool used in many computing devices. The input provided by a mouse can be relatively simple—a location and the state of various buttons or scroll-wheels featured by the mouse. Many existing touch screen devices provide functionality similar to that of a mouse by allowing a user to specify a single particular location by pressing a stylus or a finger against it.
Existing operating systems (OSs) can provide, for software applications running thereon, various tools intended to make user interaction via a graphical user interface and a mouse or a mouse-like user input easier. For example, an OS utility can allow a software application to define and register a widget (e.g., a button or a scroll bar). The OS utility can track when the user clicks on the widget with a mouse and can alert the software application. This eases and simplifies the development of software applications because each application need not keep track of mouse movements.
Recent developments in user interface technology have brought forth the multi-touch panel. An exemplary multi-touch panel is described in U.S. patent application Ser. No. 11/649,998 filed on Jan. 3, 2007 and entitled “Proximity and Multi-Touch Sensor Detection and Demodulation” (incorporated by reference herein in its entirety).
One of the advantages of a multi-touch panel can be that it detects multiple touch events at multiple locations on the panel at the same time. Thus, a multi-touch panel can provide not only a single location of interaction (as many existing touch panels) but a map of all the parts of the panel that are presently being touched. This can allow for much richer user interaction than previous input devices.
However, a multi-touch panel can also require that much more data be processed by various applications taking advantage of it. Specifically, applications utilizing a multi-touch panel may need to process an entire map specifying the locations being currently touched, instead of a single mouse click location. This can result in much higher processing requirements for running applications on a multi-touch enabled device.